Host adapter
Encyclopedia
Computer hardware
Personal computer hardware are component devices which are typically installed into or peripheral to a computer case to create a personal computer upon which system software is installed including a firmware interface such as a BIOS and an operating system which supports application software that...
, a host controller, host adapter, or host bus adapter (HBA) connects a host system (the computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
) to other network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
and storage
Computer storage
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is one of the core functions and fundamental components of computers....
devices. The terms are primarily used to refer to devices for connecting SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
, Fibre Channel
Fibre Channel
Fibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
and eSATA
Sata
Sata is a traditional dish from the Malaysian state of Terengganu, consisting of spiced fish meat wrapped in banana leaves and cooked on a grill.It is a type of Malaysian fish cake, or otak-otak...
devices, but devices for connecting to IDE, Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
, FireWire, USB and other systems may also be called host adapters. Recently, the advent of iSCSI
ISCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
and Fibre Channel over Ethernet
Fibre Channel over Ethernet
Fibre Channel over Ethernet is an encapsulation of Fibre Channel frames over Ethernet networks. This allows Fibre Channel to use 10 Gigabit Ethernet networks while preserving the Fibre Channel protocol...
has brought about Ethernet HBAs, which are different from Ethernet NICs in that they include TCP Offload Engine
TCP Offload Engine
TCP offload engine or TOE is a technology used in network interface cards to offload processing of the entire TCP/IP stack to the network controller...
s. There are also converged HBAs that support both Ethernet and Fibre Channel called Converged Network Adapters (CNAs)
Converged Network Adapter
A converged network adapter , also called a converged network interface controller , is a computer input/output device that combines the functionality of a Host Bus Adaptor to a storage area network with a network interface controller for a general-purpose computer network.-Support :Some products...
.
SCSI
A SCSI host adapter connects a SCSI bus to a computer. The host adapter bridges the physical and logical chasm that separates the SCSI bus from the host computer's internal bus. Modern host adapters contain all the electronics and firmwareFirmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
required to execute SCSI transactions, and often include a BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
that not only allows the host system to boot from a SCSI device, but also facilitates configuration of the host adapter. Typically a device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
, linked to the operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
, controls the host adapter itself.
In a typical parallel SCSI
Parallel SCSI
Parallel SCSI is one of the interface implementations in the SCSI family. In addition to being a data bus, SPI is a parallel electrical bus: There is one set of electrical connections stretching from one end of the SCSI bus to the other. A SCSI device attaches to the bus but does not interrupt it...
subsystem, each device has assigned to it a unique numerical ID. As a rule, the host adapter appears as SCSI ID 7, which gives it the highest priority on the SCSI bus (priority descends as the SCSI ID descends; on a 16-bit or "wide" bus, ID 8 has the lowest priority, a feature that maintains compatibility with the priority scheme of the 8-bit or "narrow" bus).
The host adapter usually assumes the role of SCSI initiator
SCSI initiator
In computer data storage, a SCSI initiator is the endpoint that initiates a SCSI session, that is, sends a SCSI command. The initiator usually does not provide any Logical Unit Numbers ....
, in that it issues commands to other SCSI devices.
A computer can contain more than one host adapter, which can greatly increase the number of SCSI devices available.
Major SCSI adapter manufacturers are HP
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
, ATTO Technology
ATTO Technology
ATTO Technology is a manufacturer of storage connectivity and infrastructure solutions for data-intensive computing environments. ATTO manufactures host bus adapters, RAID adapters, Fibre Channel switches, protocol conversion bridges, RAID storage controllers, Mac OS X iSCSI initiator software and...
, Promise Technology
Promise Technology
PROMISE Technology, Inc. is a Taiwanese computer hardware manufacturing company. A longtime manufacturer of hard disk controllers, they presently manufacture RAID host adapter cards and have recently introduced a NAS enclosure....
, Adaptec
Adaptec
Adaptec is a computer hardware brand owned by PMC-Sierra that is used on some of its host adapters for connecting storage devices to computers. The production line of Adaptec is in Indonesia. Products are made to interface with SCSI, Serial ATA, and Serial attached SCSI. Some of its host adapters...
, and LSI Logic. LSI, Adaptec, and ATTO currently offer PCIe SCSI adapters which fit in new Apple Mac, on Intel PCs, and low-profile motherboards from companies like HP (which now lack SCSI support due to the inclusion of SAS and/or SATA connectivity)..
Fibre Channel
Today, the term host bus adapter (HBA) is most often used to refer to a Fibre ChannelFibre Channel
Fibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
interface card. Fibre Channel HBAs are available for all major open systems, computer architectures, and buses, including PCI
Peripheral Component Interconnect
Conventional PCI is a computer bus for attaching hardware devices in a computer...
and SBus
SBus
SBus is a computer bus system that was used in most SPARC-based computers from Sun Microsystems and others during the 1990s...
(obsolete today). Each HBA has a unique World Wide Name
World Wide Name
A World Wide Name or World Wide Identifier is a unique identifier which identifies a particular Fibre Channel, Advanced Technology Attachment or Serial Attached SCSI target...
(WWN), which is similar to an Ethernet MAC address
MAC address
A Media Access Control address is a unique identifier assigned to network interfaces for communications on the physical network segment. MAC addresses are used for numerous network technologies and most IEEE 802 network technologies, including Ethernet...
in that it uses an OUI
Organizationally Unique Identifier
An Organizationally Unique Identifier is a 24-bit number that is purchased from the Institute of Electrical and Electronics Engineers, Incorporated Registration Authority...
assigned by the IEEE. However, WWNs are longer (8 bytes).
There are two types of WWNs on a HBA; a node WWN (WWNN), which is shared by all ports on a host bus adapter, and a port WWN (WWPN), which is unique to each port. There are HBA models of different speeds: 1Gbit/s, 2Gbit/s, 4Gbit/s, 8Gbit/s, 10Gbit/s and 20Gbit/s.
The major Fibre Channel HBA manufacturers are QLogic
QLogic
QLogic Corporation is an Aliso Viejo, California-based designer and supplier of storage networking, high performance computing networking, and converged infrastructure solutions...
and Emulex
Emulex
Emulex Corporation is a California based manufacturer of storage networking infrastructure solutions. The company's products include Fibre Channel host bus adapters , Fibre Channel over Ethernet converged network adapters , embedded storage switches, storage I/O controller and SAN storage switch...
. As of mid-2009, these vendors shared approximately 90% of the market. Other manufacturers include Agilent
Agilent Technologies
Agilent Technologies , or Agilent, is a company that designs and manufactures electronic and bio-analytical measurement instruments and equipment for measurement and evaluation...
, ATTO
ATTO Technology
ATTO Technology is a manufacturer of storage connectivity and infrastructure solutions for data-intensive computing environments. ATTO manufactures host bus adapters, RAID adapters, Fibre Channel switches, protocol conversion bridges, RAID storage controllers, Mac OS X iSCSI initiator software and...
, Brocade
Brocade Communications Systems
Brocade Communications Systems, Inc. , based in Silicon Valley , is a vendor of storage area network hardware and software. The company also designs, manufactures, and sells networking products and management applications for local, metro, and wide area networks...
, and LSI.
HBA is also known to be interpreted as High Bandwidth Adapter in cases of Fibre Channel controllers.
InfiniBand
The term host channel adapter (HCA) is usually used to describe InfiniBandInfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
interface cards.
ATA
ATA host adapters are integrated into motherboards of most modern PCPersonal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
s. They are often improperly called disk controllers. The correct term for the component that allows a computer to talk to a peripheral bus is host adapter . A proper disk controller
Disk controller
The disk controller is the circuit which enables the CPU to communicate with a hard disk, floppy disk or other kind of disk drive.Early disk controllers were identified by their storage methods and data encoding. They were typically implemented on a separate controller card...
only allows a disk to talk to the same bus.
SAS and SATA
SASSerial Attached SCSI
Serial Attached SCSI is a computer bus used to move data to and from computer storage devices such as hard drives and tape drives. SAS depends on a point-to-point serial protocol that replaces the parallel SCSI bus technology that first appeared in the mid 1980s in data centers and workstations,...
or serial-attached SCSI is the current connectivity to replace the previous generation parallel-attached SCSI (PAS) devices. Ultra320 was the highest level of parallel SCSI available, but SAS has since replaced it as the highest-performing SCSI technology.
SATA
Sata
Sata is a traditional dish from the Malaysian state of Terengganu, consisting of spiced fish meat wrapped in banana leaves and cooked on a grill.It is a type of Malaysian fish cake, or otak-otak...
is a similar technology from the aspect of connection options. HBAs can be created using a single connector to connect both SAS and SATA devices.
Major SAS/SATA adapter manufacturers are Promise Technologies, Adaptec
Adaptec
Adaptec is a computer hardware brand owned by PMC-Sierra that is used on some of its host adapters for connecting storage devices to computers. The production line of Adaptec is in Indonesia. Products are made to interface with SCSI, Serial ATA, and Serial attached SCSI. Some of its host adapters...
, HP
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
, QLogic
QLogic
QLogic Corporation is an Aliso Viejo, California-based designer and supplier of storage networking, high performance computing networking, and converged infrastructure solutions...
, Areca, LSI and ATTO Technology
ATTO Technology
ATTO Technology is a manufacturer of storage connectivity and infrastructure solutions for data-intensive computing environments. ATTO manufactures host bus adapters, RAID adapters, Fibre Channel switches, protocol conversion bridges, RAID storage controllers, Mac OS X iSCSI initiator software and...
.
eSATA
External Serial ATA disk enclosureDisk enclosure
A disk enclosure is essentially a specialized chassis designed to hold and power disk drives while providing a mechanism to allow them to communicate to one or more separate computers. Drive enclosures provide power to the drives therein and convert the data sent across their native data bus into a...
s and drives are increasingly common in the consumer computing market, but not all SATA-compatible motherboards and disk controller
Disk controller
The disk controller is the circuit which enables the CPU to communicate with a hard disk, floppy disk or other kind of disk drive.Early disk controllers were identified by their storage methods and data encoding. They were typically implemented on a separate controller card...
s include external SATA ports. As such, adapters to connect external SATA devices to ports on an internal SATA bus are commonly available.
Mainframe I/O channels
In the mainframeMainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
field, the terms host adapter or host bus adapter were traditionally not used.
A similar goal is achieved since 1960s with a different technique: I/O channel, or simply channel, is a separate processor that can access main memory independently, in parallel with CPU (like later DMA
Direct memory access
Direct memory access is a feature of modern computers that allows certain hardware subsystems within the computer to access system memory independently of the central processing unit ....
in personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
field), and that executes its own I/O-dedicated program
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
s when pointed to such by the controlling CPU.
Protocols used by I/O channels to communicate with peripheral devices include ESCON
ESCON
ESCON is a data connection created by IBM, and is commonly used to connect their mainframe computers to peripheral devices such as disk storage and tape drives. ESCON is an optical fiber, half-duplex, serial interface. It originally operated at a rate of 10 Mbyte/s, which was later increased to...
and newer FICON
FICON
FICON is the IBM proprietary name for the ANSI FC-SB-3 Single-Byte Command Code Sets-3 Mapping Protocol for Fibre Channel protocol. It is a FC layer 4 protocol used to map both IBM’s antecedent channel-to-control-unit cabling infrastructure and protocol onto standard FC services and infrastructure...
.
See also
- Network cardNetwork cardA network interface controller is a computer hardware component that connects a computer to a computer network....
- Fibre Channel Host Bus Adapters
- Converged Network AdapterConverged Network AdapterA converged network adapter , also called a converged network interface controller , is a computer input/output device that combines the functionality of a Host Bus Adaptor to a storage area network with a network interface controller for a general-purpose computer network.-Support :Some products...
(CNA) - Host controller interface for USB and FireWire host adapter information